I've tried the Sylvania 6J5GT and Mullard CV1932
but the pair of Hytron labelled Mullard 6P5GTs
leaves the others in the dust 8^D.
Slightly lower gain but much better sound
makes the others sound harsh in comparison.
Maybe it's the round plates - I don't know.
I use them in my DIY SE KT66/6L6G amp.
Paired with Tungsol Re-issue 6L6Gs in the coke bottles
brings everything into my living room.
Paired with the Genelex KT66s and
you are at the concert front center.

I used to have boxes of these types, but I'm gradually selling them off on ebay since I use DHT small tubes now. But these 6J5 types remain one of the great bargains in audio. Standouts are, in my opinion

6P5G
6P5GT
2C22/7193
CV1932

But then there are all the following:
Pinnacle 6J5GT - Morgan loved this in his Valve Amplifiers - he tested it as ultra low distortion
6C5G - very interesting one this, especially the Fivre. Has a mesh screen
6J5G - loads of interesting and good sounding ones here - round anodes, flat anodes etc. Very good value, cool ST shape
6L6G - not to be overlooked - similar anode structure to the wonderful 6P5GT, cool ST shape